Bhagavad Gita Chapter 13 Verse 20
भगवद् गीता अध्याय 13 श्लोक 20

प्रकृतिं पुरुषं चैव विद्ध्यनादी उभावपि।
विकारांश्च गुणांश्चैव विद्धि प्रकृतिसंभवान्।।13.20।।



हिंदी अनुवाद - स्वामी रामसुख दास जी ( भगवद् गीता 13.20)
।।13.20।।प्रकृति और पुरुष -- दोनोंको ही तुम अनादि समझो और विकारों तथा गुणोंको भी प्रकृतिसे ही उत्पन्न समझो। कार्य और करणके द्वारा होनेवाली क्रियाओंको उत्पन्न करनेमें प्रकृति हेतु कही जाती है और सुखदुःखोंके भोक्तापनमें पुरुष हेतु कहा जाता है।


English Translation of Sanskrit Commentary By Sri Shankaracharya's
13.20 Viddhi, know; ubhau, both; prakrtim Nature; and also the purusam, individual soul;-these two; Nature and the soul. the aspects of God-to be api, verily; anadi, without beginning. Those two that have no beginning (adi), are anadi. Since the godhood of God is eternal, therefore it is logical that even His aspects also should have eternality. For Gods god-hood consists verily in having the two aspects. Those two aspects through which God becomes the cause of creation, continuance and dissolution of the Universe, and which are beginningless, are the sources of mundane existence.
Some interpret the phrase anadi in the tatpurusa [Tatpurusa: Name of a class of compounds in which the first member determines the sense of the other members, or in which the last member is defined or alified by the first, without losing its original independence.-V.S.A.] sense of na adi, not primeval (not cause). (According to them) thery indeed is established the causality of God. Again, if Nature and soul themselves be eternal, the mundane existence would surely be their creation, and the causality of the mundane existence would not be Gods.
That is wrong because, there being nothing to rule over before the emergence of Nature and soul, there will arise the contingency of God ceasing to be God! And if the mundane state be uncaused [Uncaused, i.e. not caused by Nature and soul, but by God independently of those two aspects.] there arises the contingency of the absence of Liberation, [If God were. Himself the sole cause of mundane existence, independently of His two aspects, then it would be endless because there would be nothing to prevent liberated souls from being put under bondage again.] the scriptures becoming useless, and the absence of bondage and freedom. On the other hand, all these become justifiable if God and the two aspects be eternal.
How?
Viddhi, know; the vikaran, modifications that will be spoken of-the intellect etc., the body and the organs; ca eva, as also; gunan, the alities (sattva etc.)-manifest in the form of the mental states of happiness, sorrow and attachment; as prakriti-sambhavan, born of Nature. Nature, Maya, is the power of God, which is the cause of the modifications and which consists of the three alities. Those modifications and alities, which have that Nature as their source,-know those modifications and alities as born of Nature, as transformations of Nature.
Which again, are those modifications and alities born of Nature?


English Translation of Commentary  - Dr. S. Sankaranarayan
13.20 See Comment under 13.23


English Translation of Ramanuja's Sanskrit Commentary
13.20 Know this Prakrti and Purusa (self) are uncreated and are beginningless. Know that the modifications, desire, hatred etc., which cause bondage, and the alities of modesty etc., which cause release, originate from Prakrti. The Prakrti, having no beginning, develops into the form of the body, and conjoint with the self, causes bondage through its own transformations such as desire and hatred. The same Prakrti, through its transformations like modesty etc., causes release. Such is the meaning.

The difference in the functions of Prakrti and Purusa in combination is stated -


Transliteration Bhagavad Gita 13.20Prakritim purusham chaiva viddhyaanaadee ubhaavapi;
Vikaaraamshcha gunaamshchaiva viddhi prakritisambhavaan.


Word Meanings Bhagavad Gita 13.20prakṛitim—material nature; puruṣham—the individual souls; cha—and; eva—indeed; viddhi—know; anādī—beginningless; ubhau—both; api—and; vikārān—transformations (of the body); cha—also; guṇān—the three modes of nature; cha—and; eva—indeed; viddhi—know; prakṛiti—material energy; sambhavān—produced by